Implosive actuation of downhole tools

ABSTRACT

An actuation and/or communication device for the downhole environment. The device includes a selectively implosion resistant canister; and an environment within the canister and releasable upon implosion of the canister. A method for actuating a downhole device and/or communicating. The method includes delivering a selectively implosion resistant canister having an environment internal to the canister releasable upon implosion of the canister to a selected location within a borehole; imploding the canister; releasing the environment; and receiving a signal generated by the release of the environment. A method for an actuating a tool and/or communicating including delivering of an implosive device to a selected location; creating a rarefaction event by imploding said device; and affecting a tool in response to the event.

BACKGROUND OF THE INVENTION

Actuation of downhole tools far from a surface location is a fact of life for an operator of a hydrocarbon exploration or production effort. Since such actuation has been necessary for a number of years, there are several different means available for remote actuation of tools. Existing means of actuation require a communication link or “conduit” to the surface such as a wireline, or a hydraulic control line, or even an optic fiber control line. While existing devices, and methods for their actuation, are effective, they all suffer from drawbacks, not the least of which is the extended communications conduit necessary to their use. Extended communication conduits make devices more complex. Moreover, the conduits are subject to damage or require costly, elaborate or time-consuming configurations to be protected. There are also limitations imposed on a well using these means since they cause a reduction in patency of the wellbore.

Other methods for actuating downhole tools include The “EDGE”™ Actuation System, commercially available from Baker Oil Tools, Houston, Tex. among other pressure actuation concepts. The “Edge”™ family of downhole tool(s) is one in which tools are selectively actuated downhole in response to unique pressure pulse sequences emanating from a pressure pulsation unit located at the surface of the well. The pulser induces hydrodynamic pressure pulses into the top of the fluid column in the well. These purposely-timed pressure pulses propagate upward and downward within the fluid column. Each of the EDGE™ enabled tools is capable of detecting and discriminating for the presence/absence of its uniquely required combination of pressure pulse amplitude and timing sequence.

This and other pressure based systems in the art, while functioning well for their intended purpose, all impose cost, logistical (size & weight), and technical limitations on operation of the well. These include: (1) pulse amplitude dampening during transit; (2) inability to ‘pulse’ into high ambient tubing pressure regimes; and (3) lengthy time delays required to allow dissipation of the high pulse amplitude ‘ringing’ within the well. Since the above described and other prior art means to actuate downhole tools each have drawbacks and limitations, additional methods and devices for downhole actuation are always well received by the art.

SUMMARY

Disclosed herein is an actuation and/or communication device for the downhole environment. The device includes a selectively implosion resistant canister; and an environment within the canister releasable upon implosion of the canister.

Further disclosed herein is a method for actuating a downhole device and/or communicating. The method includes delivering a selectively implosion resistant canister having an environment internal to the canister releasable upon implosion of the canister to a selected location within a borehole; imploding the canister; releasing the environment; and receiving a signal generated by the release of the environment.

Yet further disclosed herein is a method for actuating a tool and/or communicating including delivering of an implosive device to a selected location; creating a rarefaction event by imploding said device; and affecting a tool in response to the event.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 schematically represent an implosive actuator moving down a wellbore to a selected depth where implosion is calculated to occur;

FIG. 6 is a cross-sectional view of an actuator of the type disclosed herein in one possible geometric shape;

FIG. 7 is a cross-sectional view of a nested embodiment; and

FIG. 8 is a cross-sectional view of a group of attached canisters.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1-5 simultaneously, a progression of an implosive downhole actuator is illustrated. A representation of a borehole 10 is repeated in each illustration. This is intended to represent the same portion of the borehole, which portion could be at any depth relative to the well system (not illustrated). In FIG. 1, an implosive actuator 12 is illustrated in a first position within the borehole 10. In FIG. 2, the actuator 12 has moved downhole by gravity, circulation, mechanical movement, etc. as illustrated by arrows and phantom representations of the actuator 12. FIG. 3 illustrates the actuator 12 reaching a selected location 14 whereat conditions in the borehole 10 and or conditions experienced by actuator 12 while traveling to the selected location 14, cause the actuator 12 to implode. Implosion of the actuator causes a localized rarefaction 16 and initiates a propagating negative pressure wave 18. The rarefaction also initiates a collapse of the fluid column above the implosive event into that region immediately following the implosion. Such collapse causes a high positive pressure event that also generates a propagating wave (positive in nature), the effect of the waves whether positive or negative is schematically illustrated in FIGS. 4 and 5. Such rarefaction and propagating negative and positive pressure waves are each employable for actuation of a downhole tool. In the case of positive pressure, the tool may be directly actuated by the pressure and in the case of negative pressure, the tool may have its own actuation capability and require only a signal, which can be provided by the negative pressure wave. The negative pressure wave (and of course the positive pressure wave too) is employable for communication with locations remote from the selected location 14 based upon propagation through the fluid column or other available media. It should be noted that sometimes in this application the term “pressure wave” is used in the singular. This is not to way that the other of the negative or positive wave is omitted but merely that one of them may be particularly relevant to the local discussion at that point of the application. The actuator 12 comprises a selectively implosion resistant canister(s) and an environment(s) internal to the canister(s), also referred to herein as a “captured environment(s)”. Each feature is discussed in more detail hereinbelow.

In one embodiment, the condition in the borehole 10 that causes implosion is pressure. The pressure is from the height of the column of fluid (depth) in the borehole elevationally higher than the selected location 14 and the density of that fluid. The controlling equation is p=rho times g times h, where p=pressure; rho=density of the fluid; g=acceleration due to gravity; and h is the height of the fluid column. In this embodiment, actuator 12 is configured to be structurally sound until reaching a selected pressure. Upon reaching that pressure, actuator 12 is configured to rupture allowing a captured environment 20 inside the actuator within canister 22 (see FIG. 6) to be rapidly exposed to the ambient higher-pressure environment 24 (see FIG. 3). The result is a localized rarefaction of the fluid at the location of the implosion. For clarity, “rarefaction” is defined as a reduction in density or pressure. Such rarefaction is, in essence, a signal. In the event that a tool is configured specifically to receive such signal or even would be reactive to such a signal, a resultant action is possible in such a tool (“tool” is used as an example here, there is intended to be no limitation upon the employment of the implosive actuation concept. For example, there may be no actual tool in the borehole 10 and the implosive event followed temporally closely by rarefaction could be used to directly affect the borehole or formation itself without departing from the scope of the invention disclosed herein). As noted above, the positive pressure wave following the negative pressure wave could also be used as either a signal or direct actuator on such tool, as desired.

The present implosive actuation method is superior to pressure based actuation methods of the prior art (surface) such as those described above in one way because of the relocation of the source of the pulse. As disclosed herein, the source of the pulse is located within close proximity to the device to be actuated. This repositioning of the pulse source at/near the targeted device: (1) eliminates pulse amplitude dissipation as a concern; (2) reduces the pulse amplitude requirements to only that necessary to radiate a distance equal to the inaccuracy of the settling/circulating time for the implosive device(s); (3) is insensitive to absolute tubing pressure levels, as such devices can be designed to implode at virtually any pressure; (4) shortens/eliminates concerns associated with delays due to ‘ringing’ by reduction of the initial pressure pulse level due to proximity to the device; and (5) significantly improves model accuracy due to reduction of the number and nature of variables associated with this method relative to those in the art.

Another use for the same embodiment is as a communicative device. This is affected by utilizing the negative pressure wave generated by the original rarefaction event (or the positive pressure wave) as a communications signal. Using time as a factor, information such as the density of the fluid in a column can be determined by using an “actuator” 12 having a known pressure rupture point. In addition, where the actuator 12 is used to actuate a tool in the downhole environment, the actuator also necessarily will create the pressure wave. Confirmation of implosion at the selected location 14, is attainable by employing a surface receiver or a downhole receiver that is receptive to the pressure wave.

In another embodiment, the tubular illustrated in FIGS. 1-5 is to be construed as a small diameter tubular such as a control line. Actuators deployed in control lines would be circulated to the desired location and the implosion could be triggered by any of the conditions noted above. This then would relieve the requirement for high surface pressures to generate an appropriate and effective signal at the downhole tool.

Because of the relative magnitude of the pressure change in the selected location 14, a relatively significant amount of “work” is achievable by actuator 12. Such work can be used to shift a deployment mechanism (not shown) or free a jammed component (not shown), etc. Similarly to the jammed component concept, an actuator 12 may be employed in a “string-shot” operation associated with a “back-off” operation such as where a bottom hole assembly is stuck in the bore and it is desired to remove as much of the drill string above the “stuck” as possible to make way for a fishing string. Such operations are known and utilize an explosive charge run to a selected location and ignited to jar a joint in the string contemporaneously with the imposition of a left turn torque on the drill string. The purpose, as will quickly be appreciated by one of skill in the art, is to jar a particular joint thereby encouraging that joint to separate rather than one farther uphole thereof. The actuator 12 of this disclosure is used to create the pressure wave that induces the jar to the joint that is desired to be released. Utilizing the actuator 12 means that the string-shot string can be eliminated altogether and that the explosive charge can be eliminated thereby also substituted for by the effective yet more easily transportable actuator 12.

In some cases, multiple pressure waves may be desirable to, for example, ensure a specific signal is received by a tool before actuation of the tool. More specifically, a hypothetical tool may require a plurality of “pulses” before it will actuate. Such arrangement will prevent premature actuation. Where multiple pulses are to be applied, one embodiment is to deploy or “drop” a plurality of actuators. Each actuator 12 will implode at the selected external pressure and create its own pressure waves. Assuming such plurality of actuators is dropped seriatim, they will create a series of implosions and resulting waves.

In another embodiment requiring multiple actuation signals, the actuator 12, referring to FIG. 7, may be constructed with multiple canisters 30, 32 and 34, each canister 30, 32 and 34 defining a specific captured environment, which may be collectively similar or individually unique. In the case of canister 30 the environment 36 is defined within the confines of canister 30, which is similar to the environment 20 in FIG. 6. In the case of canister 32, the captured environment 38 is defined between canister 32 and canister 30. The environment 38 may have the same properties as environment 36 or may have different properties. Canister 34 then bounds, with canister 32 an environment 40, which again may have properties the same as or different from environment 36 or 38. “Properties” for example, may be pressure, chemical composition or species (solids, gasses, liquids) that will have a specific effect on what and how the implosion event will affect the selected location 14. It should be noted that while these canisters 30, 32 and 34 are illustrated in FIG. 7, there is no limit to the number of canisters that may be nested together or otherwise attached together (i.e. externally attached as opposed to nested, see FIG. 8) other than typical size limitations inherent in the borehole 10.

The embodiment of FIG. 7 will inherently provide a cascaded implosive event as the rarefaction caused by the first implosion of canister 34 will momentarily reduce the environmental pressure at canister 32. Once the negative pressure wave propagates, higher pressure will once again control (and might indeed be the high pressure created by the collapse of the fluid column into the rarefaction volume) thereby rupturing canister 32. The process will repeat for canister 30 and any additional canisters. The cascade implosion results in a rapid series of rarefaction events and pressure waves usable for actuation and/or communication. It is further noted that the cascade embodiment can use different communication materials in defined environments such that a first implosion will send a signal, the second implosion will release a chemical and the third implosion will do something else or one of these again. Multiple actions can thus be taken with a single actuator 12 or a coded series of actions can be used so that premature actuation of a target device can be avoided. Where a chemical is to be within one or more of the canisters, it will be small in displacement relative to the defined environment if it is solid or can be frangible such that it will yield under pressure. Also note the chemical embodiments can use the chemically activated canisters too (discussed hereunder).

In an alternate embodiment, the canister 22 (or multiple canisters) may be chemically reactive as opposed to pressure reactive, or both. In one iteration of this embodiment, the actuator 12 can be utilized to determine the depth at which a water breakthrough has occurred by making the canister(s) out of a water-soluble material. In such an embodiment the canister 22, for example, would be capable of withstanding the pressure that exists for wherever the deepest location it might be able to attain once deployed, meaning that the actuator 12 will not implode due to pressure. Such embodiment would not however be able to remain structurally sound when exposed to a selected concentration of water. In use, this embodiment would move through the borehole 10 by gravity, circulation, mechanical movement (just like the other embodiments), etc. and if and when it encounters a water breakthrough, the canister material would break down and the actuator 12 would implode thereby producing a rarefaction and sending a wave that can be received by a receiver downhole or at the surface. Since the density of the fluid in the borehole 10 will be known for other reasons, time to the receipt of the pressure wave may be used to determine location of the water breakthrough so that corrective action may be taken.

The actuator disclosed herein is also capable of facilitating flow for the well by “jarring” the formation or tools that have had flow rates restricted by such as paraffin or sand. The pressure wave produced during the implosion can lessen such flow restrictions and return normal flow.

It is also to be appreciated that in each of the multiple canister embodiments, individual canisters of the plurality of canisters (whether externally attached, nested or dropped in a grouping) may be configured to implode due to different environments than other canisters. For example, where three canisters are attached, nested or otherwise grouped, one may implode due to chemical species interaction while another may implode due to pressure, and so on whereby specific exposures and rarefaction events can be planned or planned for to achieve the desired result. The possibility for combination of these features is extensive. 

1. An actuation and/or communication device for the downhole environment comprising: a selectively implosion resistant canister; and an environment within the canister and releasable upon implosion of the canister.
 2. The actuation and/or communication device as claimed in claim 1 wherein the environment is gaseous.
 3. The actuation and/or communication device as claimed in claim 1 wherein the environment is a frangible solid.
 4. The actuation and/or communication device as claimed in claim 3 wherein the solid fills the canister.
 5. The actuation and/or communication device as claimed in claim 1 wherein a plurality of canisters is nested.
 6. The actuation and/or communication device as claimed in claim 1 wherein a plurality of canisters are attached to one another.
 7. The actuation and/or communication device as claimed in claim 1 wherein the canister is pressure implodable.
 8. The actuation and/or communication device as claimed in claim 1 wherein the canister is water soluble.
 9. The actuation and/or communication device as claimed in claim 1 wherein the canister is chemically implodable.
 10. The actuation and/or communication device as claimed in claim 5 wherein the plurality of canisters contain more than one type of environment among them.
 11. The actuation and/or communication device as claimed in claim 1 wherein the environment is chemically active.
 12. The actuation and/or communication device as claimed in claim 6 wherein the plurality of canisters attached to one another include at least one that is responsive to a different environment for implosion.
 13. The actuation and/or communication device as claimed in claim 12 wherein the different environment is a different pressure.
 14. The actuation and/or communication device as claimed in claim 12 wherein the different environment is a different chemical.
 15. A method for actuating a downhole device and/or communicating, comprising: delivering a selectively implosion resistant canister having an environment internal to the canister releasable upon implosion of the canister to a selected location within a borehole; imploding the canister; releasing the environment; generating a signal by the release of the environment.
 16. The method for actuating a downhole device and/or communicating as claimed in claim 15 wherein the imploding is caused by exposing the canister to a selected pressure.
 17. The method for actuating a downhole device and/or communicating as claimed in claim 15 wherein the imploding is caused by exposing the canister to a selected chemical.
 18. The method for actuating a downhole device and/or communicating as claimed in claim 15 wherein the imploding is caused by exposing the canister to water.
 19. The method for actuating a downhole device and/or communicating as claimed in claim 12 wherein the method includes delivering a plurality of canisters to the selected location.
 20. A method for an actuating a tool and/or communicating, comprising: delivering of an implosive device to a selected location; creating a rarefaction event by imploding said device; affecting a tool in response to the event.
 21. The method of claim 20 wherein the affecting is actuating.
 22. The method of claim 20 wherein the affecting is jarring.
 23. The method of claim 20 wherein the delivery is by circulation. 